The present invention relates to a bagging apparatus for bagging free-flowing material into bags and for sealing such filled bags, such apparatus including means for receiving and temporarily storing the material, at least one apparatus for weighing and filling the material into a bag, at least one system for transport of the bagged material, and means for closing of such filled bag.
There has been known for a long time a movable apparatus for bagging of free-flowing material such as fertilizer and grain. The material is transported in bulk overseas to remote locations. Normally, the bulk material is discharged from a docked ship by using a mechanical grab. The free-flowing material is supplied to hoppers or silos for storage, located at a quay or nearby the docked ship.
The hoppers of well known bagging plants are made very robust and have coarse grating enabling the grab to crush any lumps of the material. Bagging is achieved by reliable volume packers located directly below the topper. The packers can be used for packing of open bags, but also for valved bags if the headroom below the hopper is increased by redesigning the construction of the hopper. This however represents a large and costly operation. Volume packers are used for bagging because they are reliable under the harsh bagging environment including vibrations, humidity, dust and temperature differences. These packers however have one main disadvantage involving inaccuracy during bagging. Such inaccuracy may be 300 gram per bag when bagging 50-litre bags. This adds up to several hundred tons per shipload. A second disadvantage of known mobile packers involves the open conditions of the supply piping with respect to static electricity and air, wherein the apparatus is unattached and unsecured and results in environment problems and production losses.
In Norwegian Patent No. 156,324 (corresponding to EP Patent No. 0,067,064) there is disclosure a mobile bagging apparatus where two containers are used for bagging free-flowing material. One upper container made according to standard dimensions comprises a silo for receiving the material, and it is fastened to a lower container which forms the bagging apparatus proper. Such apparatus has concentrated on providing a system that can be transported by a container-ship, rather than solving the problems related to bagging by a mobile bagging apparatus. Such apparatus, because of the low headroom in the container, can be used only for bagging open bags, and further it has room or space only for one bagging run. Such solution inherently has restricted use and low production capacity.
Also, because the upper container rests on the lower container, vibrations and shocks from the discharging apparatus will be transmitted to the lower container that includes the weighing equipment. Such vibrations and shocks are harmful to the weighing equipment and will disrupt the accuracy thereof. Thus, a mechanical weighing apparatus without electronic control is used. However, such a mechanical weighing apparatus has low accuracy and capacity, and this increases the drawback of such known system.